Strontium is a silvery gray element that was first discovered in the early 1800s. It is a soft, easily worked metal that resembles calcium. Because of this similarity, strontium can replace calcium in certain processes in the body. Strontium may promote extra calcium uptake into bones.

Strontium has sixteen forms: twelve radioactive and four nonradioactive. Strontium-88 is the most common form, making up 83% of natural strontium. Strontium-90 is a radioactive form that earned public attention for being a dangerous byproduct released from nuclear weapons testing in the 1950s. Strontium-89 chloride is another radioactive form used to reduce pain in people with cancer and is the active ingredient in the U.S. Food and Drug Administration (FDA)-approved drug Metastron®.

In the United States, strontium salts (carbonate, chloride, citrate, gluconate, sulfate, etc.) are available as dietary supplements. According to secondary sources, the most common form of strontium found in dietary supplements is strontium chloride. Strontium chloride, as well as strontium acetate, may be found in dental products like Sensodyne®, a toothpaste used to reduce pain caused by teeth sensitivity.

In Europe, strontium ranelate is a prescription drug used for osteoporosis. It is marketed under the trade names Protos®, Protelos®, Osseor®, Bivalos®, and Protaxos®. According to previous and ongoing research, strontium ranelate may prevent bone loss, increase bone strength, and reduce fractures in postmenopausal women. It may also benefit people with osteoarthritis.

Strontium nitrate has been studied for skin irritation and inflammation caused by allergic reactions to cosmetics, personal care products, and drugs, and during occupational exposure. However, large, well-designed trials are needed before a conclusion can be made.

According to experts, taking calcium and strontium at the same time may reduce strontium absorption. Strontium ranelate should not be used in people with kidney problems. Preliminary studies suggest that strontium may increase the risk of artery blockages.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

Strontium-89 chloride may relieve bone pain associated with prostate and breast cancer. Metastron® is an FDA-approved drug for this use. In clinical research, up to 80% of people reported improvement and 10% reported complete pain relief.

A

Strontium chloride and strontium acetate, found in dental products like Sensodyne® and Hyposen®, are used for reducing the pain and discomfort of sensitive teeth. Studies suggest that brushing twice daily with toothpastes containing strontium acetate has helped with long-lasting pain relief.

A

Clinical studies have found that strontium ranelate can prevent bone loss, increase bone strength, and reduce fractures in postmenopausal women. Evidence suggests that treatment compliance may further reduce the risk of hip fractures.

A

Some studies have found that strontium ranelate may reduce back pain and slow the development of spinal osteoarthritis. However, more studies are needed to confirm these findings.

B

Strontium salts been found to have an anti-itch, anti-irritant effect against some cosmetics and chemical peels, without numbing side effects. Studies found that applying 20% strontium nitrate to the arm for 30 minutes decreased allergic itch. However, more studies are needed before a clear conclusion can be made.

B

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

Servier, the manufacturer of various strontium ranelate products, advises patients with severe kidney impairment not to use the product.

To treat osteoarthritis, two grams of strontium ranelate has been taken by mouth daily for three years.

To treat osteoporosis, 500-2,000 milligrams of strontium ranelate has been taken by mouth daily for up to eight years.

To reduce tooth sensitivity, a 10% strontium chloride hexahydrate dentifrice has been used for six months, and toothpastes containing 8% strontium acetate and sodium fluoride have been used twice daily.

To remove dental plaque, a solution containing chlorhexidine gluconate, sodium fluoride, and strontium has been used for two weeks.

To treat skin irritation, 20% strontium nitrate has been applied to the skin once for 20-30 minutes.

To reduce pain associated with cancer, injections of Metastron® ranging from 0.6 megabecquerels (MBq) per kilogram to 400MBq of strontium per person have been given up to 10 times in three months.

To prevent the recurrence of eye disorders (specifically, pterygium), strontium-90 radiation therapy has been administered by eye applicator for a total dose of 30 gray (Gy), given in 3 doses (10Gy weekly on days 1,8, and 15).

Children (under 18 years old)

There is no proven safe or effective dose for strontium in children.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid in people with known allergy or sensitivity to strontium.

Side Effects and Warnings

Strontium is likely safe when taken by mouth in amounts normally found in food, when used to relieve bone pain associated with cancer in the form of FDA-approved products such as Metastron®, and when used to relieve pain associated with tooth sensitivity in the form of FDA-approved products such as Sensodyne®.

Strontium is possibly safe when used to treat osteoporosis in postmenopausal women, used in a dental rinse to remove plaque, or applied to the skin to reduce allergic irritation to chemicals.

Strontium may interfere with blood and urine colorimetric measurements of calcium. Patients should inform their radiologist of strontium use. Strontium ranelate may cause a severe and life-threatening allergic reaction.

Strontium may increase the risk of bleeding. Caution is advised in people with bleeding disorders or other blood disorders (such as low platelet counts and low white blood cell counts) or in those taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.

Use cautiously in children or in people with kidney dysfunction or Paget's disease.

At least six months should be given when switching from a bisphosphonate to strontium.

Avoid in people with severe kidney impairment, known allergy to strontium or any component of the formulation, or in those who are pregnant or breastfeeding. Strontium found in toothpaste, however, appears to be safe during pregnancy and lactation.

Avoid strontium ranelate in people using tetracycline or quinolone antibiotics or in those with phenylketonuria (disorder in which a person is unable to properly break down the amino acid phenylalanine).

Avoid intravenous strontium-89 (Metastron®) in people with incontinence or compromised bone marrow.

Pregnancy and Breastfeeding

There is currently a lack of high-quality scientific evidence on the use of strontium during pregnancy or breastfeeding. Strontium found in toothpaste or taken by mouth in amounts normally found in food is likely safe during pregnancy and breastfeeding. Strontium-89 is radioactive and should be avoided during pregnancy and breastfeeding, as it may harm babies.

Strontium may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

Strontium may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.